Fire with fire egh?!

Background: ex and I split up last year due to him being unfaithful. This was our second and final split. In 2012 he saw our DS once! The whole year, in 2011 and 2016 his contact was minimul to say the least.

Now he sees DS twice weekly on the condition I let DS go to his Dad's new partners house.If not he threatens court action!In the past month or so DS has been wary of going, he has come back smelly, injured and thirsty on several occasions which is disstressing for me.Alongside this DS is suffering awful anxiety issues due to seperation issues e.g. hates going to school,out of school clubs - basically anything that means I am not there. I took DS to the doctor who said he may have to be refered to CAHMS if his anxiety continues and the doctor has pinpoint DS Father's inconsistent parenting as the cause.DS Dad demanded the 2 vists a week and I gave in as I believe DS seeing his Dad is good for him, (until the anxiety problems started) since then I have been wary of sending DS due to the state he comes back in and his mental health.Today I informed my ex DS does not want to go next Monday and that he has an appointment on Friday meaning DS will be late coming.Ex has once again threatened me with court!!I find it scary as my parents went through court and it was a bad time in my life and I still resent my Dad for doing putting me and my mum through it, I do not want that for my DS, especially with his anxiety problems.What do I do?! I feel if he did take me to court I have a lot of mitigating factors and he has very few. He gets his 2 days a week even though he has caused DS problems I do my hardest to encourage DS to go (but I never make him if he does not want to).I don't want to fight fire with fire and have the whole court battle.Oh DS Dad said him and his new partner would go for full custody which just breaks me.Ex has been in and out of DS life when he pleases. Me I have been there everyday, I don't take drugs or drink or smoke, I am working 2 jobs and at university.My head is all over, I just need advice, support maybe on what I should do next.Sorry for the long post!

Didn't want to read and not post, I really feel for you and your DS. What a stressful situation for you both. Personally I would go to either the citizens advice or a solicitor to find out exactly where you stand and work from there. I've no idea how much that would be though. Do you have other support in rl? Hope someone will be along with more advice soon.